Safety System Design Simulation for Transcutaneous Electrical Nerve Stimulator using Electrode Contact Test

TENS Transcutaneous Electrical Nerve Stimulator is a therapeutic device used to deliver electric current through one's skin. As the device is used on the human body, safety concern becomes a matter that needs special attention. One option for electrical safety is testing whether the electrode has attached properly to the skin. The test is done in the interval of the simulator pulse. This option is used to protect users from electrical shock that can be caused from this device. Using 74HC4066 as the analog switch, this design can support the TENS specification.